Unless otherwise indicated herein, the devices and approaches described in this section (“Background of the Invention”) are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
The present application relates to a chamber for removing substances from a fluid. Also disclosed is a container for adsorbing fuel vapor from a fuel tank of a vehicle, the container including the chamber. In addition, a method of manufacturing the chamber is also disclosed.
Forming an adsorbing structure can be expensive. An adsorbing structure may be formed from oxygen containing compounds, carbon based compounds, or polymer based compounds. Other compounds are also possible. In some cases, high temperatures (e.g., 1100° C.) may be required to form the structure. Further, it may be difficult to extrude a mixture of adsorbent material (e.g. activated carbon) and form the adsorbent material, along with additional material (e.g., ceramic), into a suitably shaped structure, such as a honeycomb. The extrusion may require a great deal of water. Further, the water must be removed from the structure before firing the structure in order to avoid damage (e.g., cracks in the structure), and removal of the water may be problematic. In particular, if the water is not removed carefully the structure may shrink or crack.
While the use of a flux material can alleviate some of the problems in forming an adsorbing structure, the process can still be time consuming and expensive.
Adsorbing material (i.e., an adsorbent material), possibly in the form of an adsorbing structure, may be used to remove substances from a fluid. Removable substances may include organic substances and non-polar adsorbates. Removable substances may include chemical agents. More specifically, removable substances may include fuel vapor (i.e., fuel tank emissions or engine exhaust, possibly containing hydrocarbon emissions), volatile organic compounds, and chemical substances such as ozone.
Adsorbing material (e.g. in the form of an adsorbing structure) may be used in an automobile engine or in an office machine such as a xerographic device. The adsorbent material may be placed within a chamber, and fluid to be acted on by the adsorbent material may be directed through the chamber.
For example, adsorbent material may be used in the context of an internal combustion engine of a motorized vehicle, such as an automobile. Fuel vapor from the engine may be directed through the chamber in order to prevent release of substances in the fuel vapor into the atmosphere. Accordingly, a port (i.e. opening or aperture) from the chamber may be connected to the fuel tank such that the fuel vapor from the fuel tank passes through the chamber and substances in the fuel vapor are adsorbed by the adsorbent material in the chamber. In some cases, multiple chambers (e.g., at least two, possibly more) may be connected to each other within a container, and a fluid such as the fuel vapor may be directed through each chamber in the container before being allowed to exit into the atmosphere. In addition, air from the atmosphere may pass through the chamber and cause adsorbed substances to exit the chamber toward the combustion engine so that they are burned in the internal combustion engine.
In summary, when the vehicle is stopped, fuel vapor from the fuel tank flows through one of the ports (e.g., a charge port) into the chamber and is adsorbed by adsorbent material in the chamber. During operation of the engine, atmospheric air is introduced through another of the ports (e.g., an atmosphere port) and the previously adsorbed fuel vapor is desorbed and carried to the engine to be combusted within the engine. There may be multiple chambers (at least two, possibly more) adapted for adsorbing and desorbing HC (hydrocarbons) or other substances within a container.
In addition to satisfactorily adsorbing and desorbing substances from a fluid, adsorbent material in the chamber should also have a sufficiently low flow resistance to air passing through the chamber. In other words, there should be an adequate flow rate of air so that air exits the chamber promptly. In particular, in the context of a vehicle, the chamber may be connected to a fuel tank of the vehicle. When the fuel tank of the vehicle is filled with liquid (e.g. gasoline) the liquid pushes air through the chamber. If adsorbent material in the chamber has a flow resistance that is too high, then it may be unacceptably difficult to refuel the vehicle. For example, air unable to exit the fuel tank through the chamber may cause the pressure in the fuel tank to rise and cause a pump to stop pumping fuel into the fuel tank. Accordingly, adsorbent material in the chamber should allow air to pass through the chamber at a rate of at least 50 to 70 l/min, at least 55 to 65 l/min, at least 58 to 62 l/min, or at least about 60 l/min. The diurnal breathing loss of substances from the chamber (e.g., evaporative emission of hydrocarbons in a three-day diurnal test) should be below 20 mg per day. Further information regarding diurnal testing and breathing loss can be found in “The California Low-Emission Vehicle Regulations”, Aug. 7, 2012 (https://www.arb.ca.gov/msprog/levprog/cleandoc/cleancomplete_lev-ghg_regs_3-12.pdf, retrieved Nov. 21, 2016).
In addition, the chamber for removing substances from a fluid should be easy and inexpensive to assemble, particularly in comparison to the adsorbing structure described above.